Direction of MOSFET in CCG3

[Anonymous]

Hello,

I am checking the circuite described in CCG3 datasheet.

Compairing Figure 2 and Figure 15, there are two MOSFETs connecting to VBUS_P_CTRL but the diection is different.

In Figure 2,   DC-DC <-> Source-Gate-Drain <-> Drain-Gate-Source.

In Figure 15, DC-DC <-> Drain-Gate-Source <-> Source-Gate-Drain.

Which flow is correct or recommend?

Best regards,

[ShifangZ_26]

Hi ,

We are recommend to DC-DC <-> Drain-Gate-Source <-> Source-Gate-Drain.

Below circuits for your reference.

Best Regards,

Lisa

[Anonymous]

Hello Lisa-san,

Thank you for your prompt response.

I think the following is general inquire but please let me know the reson.

Q1) Why do you recommend the order, D-G-S, S-G-D?

Q2) Why do we need 2 MOSFET on the line?

Q3) The current on N-MOS flows Drain to Sorce because gate voltage should be higher than source voltage.

     Why 2nd MOFET conneting to VBUS_P_CTRL1 is sorce is connected to DCDC?

Best regards,

[ShifangZ_26 · Accepted solution]

Q1) Why do you recommend the order, D-G-S, S-G-D?

>> If I recommend to use S-G-D, D-G-S. there are two cases and fake (The current will streaming through body-diode) one of N MOS FET in this case:

The current from left to right, the first N MOS FET is fake.

The current from right to left, the second N MOS FET is fake.

Q2) Why do we need 2 MOSFET on the line?

>> If there is only one MOS FET, you will lose above explain for both direction. This is the risk. We only design with best practice.

Q3) The current on N-MOS flows Drain to Sorce because gate voltage should be higher than source voltage.

     Why 2nd MOFET conneting to VBUS_P_CTRL1 is sorce is connected to DCDC?

>> Please kindly notice that all of VBUS_P_CTRL1/2 of CCG3 is connected to CCG3.

Best Regards,

Lisa